Russian River: Drought adds stress to frost protection plans

Sonoma County winegrape grower Doug McIlroy checks one of his overhead sprinklers to make sure it is operating properly. When they are activated, overhead sprinklers provide frost protection.
Photo/Steven Knudsen

This diesel engine at Doug McIlroy’s Sonoma County vineyard is used to draw water from his well and run it through the vineyard’s sprinkler system.
Photo/Steven Knudsen

For the next several weeks, winegrape growers with vineyards along the Russian River in Mendocino and Sonoma counties will be sleeping fitfully, with one ear tuned to their frost alarms.

The mid-March to mid-May time frame is when their newly awakening vines put forth buds and leaves as they emerge from winter dormancy. It is also the period when severe frosts can cause serious damage to the tender, young shoots.

What makes this year particularly stressful for winegrape growers is the tight water supply and the knowledge that any direct diversions of water from the Russian River or its tributaries for frost protection could affect salmon and steelhead in the river that are protected by the Endangered Species Act.

The practice of using sprinklers to provide a protective covering to new vine shoots has been at the center of a dispute that began following a series of unusually frigid nights in the spring of 2008. Government biologists said water diversions by farmers resulted in two instances of stranding young, protected salmon in streams.

Many winegrape growers have created small, off-stream reservoirs in the past two or three years, to assure they would have water available for frost protection. Those growers say they should be OK if 2014 brings a mild frost season. However, if there are several frost events between now and mid-May, they may have difficulty replenishing those reservoirs from the river.

"Normally, we say we are out of the woods by Mother's Day in May, so we've got a ways to go," said Potter Valley winegrape grower Janet Pauli. "We have been told by some of the weather forecasters that they are not anticipating an awfully cold frost season this year. Maybe we will sneak by without frost protection."

Some years, she said, frost protection has only been needed for a night or two, "but we've also had years when we had 25 nights in a row of frost."

Growers who do not have off-stream reservoirs or wells are the most vulnerable, said Devon Jones, executive director of the Mendocino County Farm Bureau.

"It is a very difficult decision to make when your crop is on the line and you know that you will have damage, but I urge growers to not direct-divert unless there is a significant flow in the river from a storm. The only two dependable sources right now are off-stream ponds and wells. For everyone else, it is not worth the risk," she said.

Growers have received letters from environmental groups threatening lawsuits if endangered fish are stranded. There is also the risk of action being taken against growers by state and federal regulators.

Jones said farmers are employing creative management strategies this year, such as cultivating land to capture more groundwater, mowing cover crops and doing long pruning to protect the vines. In some of the less hilly areas, wind machines can provide frost protection and "pretty much every portable wind machine in the Anderson Valley that our local suppliers can get their hands on has been snapped up," she said.

Sean White, manager of the Russian River Flood Control District in Mendocino County, said winegrape growers and water officials are all "pulling together" to make the most with what water is available.

"I think it is going to be a very tough year and people are going to be very judicious with the use of water for both frost protection and summer irrigation. But if we take everything we have learned over the past six years and put it all into motion this year, we are going to make it—but just barely," White said.

He said farmers will need to be "both diligent and intelligent" to protect both the 2014 crop and "the long-term future of viticulture in this valley," as state water regulators consider either banning or severely restricting agricultural water diversions from the Russian River and tributaries.

Rain in recent weeks has helped with both groundwater levels and the moisture profile in the soil, and has allowed growers to delay their initial irrigation.

"This situation now is a lot better than it was back in January, that's for sure," said Doug McIlroy, Sonoma County winegrape grower and director of wine growing for Rodney Strong Winery. "People who have wells along the Russian River are in pretty good shape right now—and if we get a little more rain, that will help even more."

McIlroy said purchases of crop insurance have gone up significantly this year as growers hedge their bets regarding potential crop loss.

"Regarding crop insurance, when I spoke to my broker I was told that everyone is buying 10 percent to 15 percent above what they normally would buy," he said.

Another Sonoma County grower, Richard Rued, who farms in several locations, said that since the 2008 frost, farmers have made significant adjustments in water use.

"I quit using overhead frost protection in Dry Creek Valley and I now use wind machines. I still use overhead sprinklers in Alexander Valley, but I wait until the last minute to start it and then I run it at very low pressure. I find it does about as good a job and uses about half the water. In the Russian River Valley, I've hooked up to the Santa Rosa wastewater (recycling) system for my overhead frost protection," he said.

Pauli said the current drought following last year's low water year has served as a wakeup call for all water users.

"I've been saying over the past several months, we can't let a perfectly good drought go to waste. We should take advantage of all the lessons we are being forced to learn and use them moving forward," she said. "We need to take full advantage of what is happening so we hopefully will not face the same situation again."

(Steve Adler is associate editor of Ag Alert. He may be contacted at sadler@cfbf.com.)

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.